Large dictionaries are available for studying or understanding the vocabulary of medieval French. Among completed works, the most useful are Frédéric Godefroy's Dictionnaire de l'ancienne langue française (10 vol., 1880-1902), Adolf Tobler and Erhard Lommatzsch'sAltfranzösisches Wörterbuch (11 vol., 1915-2002) and Walther von Wartburg's Französisches Etymologisches Wörterbuch (25 vol., 1922-2002). Works in progress include the Dictionnaire Etymologique de l'Ancien Français, begun in 1971 by Kurt Baldinger, continued by Frankwalt Möhren and now by Thomas Städtler; Robert Martin's Dictionnaire du Moyen Français, the 2015 version of which has just been put online; and theAnglo-Norman Dictionary which, after its 1st edition from 1977 to 1992, is now on the Internet in its2nd edition, edited by David Trotter until his recent death. But what was missing was a one-volume working tool based on the latest lexicographical findings. The Dictionnaire du français médiéval I published in 2015 (Les Belles Lettres) aims to remedy this deficiency.
The three major completed dictionaries naturally serve as a basis for writing each article. But nothing can be done mechanically. We must always be vigilant to avoid repeating the mistakes of our predecessors. To achieve this, it is sometimes necessary to go back to handwritten sources. For example, Godefroy's reading of the word airon in Gautier de Coinci's Les Miracles de Nostre Dame is a misreading of the lesson arçon by Abbé Poquet, which the lexicographer collected without examination, attributing it to the manuscript known as de Soissons (Bibliothèque nationale de France, nouvelles acquisitions françaises 24541). Similarly, the word arrerai, cited without definition by Tobler and Lommatzsch from Guillaume Guiart's La Branche des royaux lignages , is a misreading by the Buchon editor, the manuscript (Bibliothèque nationale de France, fonds français 5698, p. 107a) giving anemis instead. If these words are not included in my dictionary, it's because I consider them non-existent.
Quotations also need to be checked, as our predecessors sometimes make mistakes in a number of ways (truncated passages, erroneous attributions, misunderstanding or dating, etc.). What's more, they don't always record the earliest testimonies. If we examine how the noun pieton "foot soldier" is treated in dictionaries, we immediately realize that they have neglected its earliest attestation, found in Guillaume Guiart's La Branche des royaux lignages (t. 2, verse 7897 of the Buchon edition; lesson confirmed by the manuscript, p. 285a). Similarly, although recent dictionaries consider Geoffroi Gaimar, author of the Estoire des Englais, to be the first to have used the adverb hastivement, it appears earlier in the Cambridge Psalter and Benedeit's Voyage de saint Brendan. Despite its limited scope, my dictionary endeavors to collect attestations neglected by our predecessors.